Ultrasonic transmitting and receiving device

ABSTRACT

An ultrasonic transmitting and receiving device wherein horns are substantially vertically fitted to a holding frame so that opening side of the respective horns will be directed downward. Each horn is provided in its throat section with an ultrasonic oscillator and in its opening with a reflector diagonally opposing the oscillator.

United States Patent 1191 Ohasi et al. Sept. 10, 1974 1 ULTRASONIC TRANSMITTING AND 2,542,594 2/1951 Tiffany 179/1 ss RECEIVING V C 2,611,445 9/1952 Meeker 181/26 2,815,087 12/1957 Delort 181/31 B [7 1 Inventors: H1r0sh1 q n yag Shmsuke 3,046,544 7/1962 Auer 181/27 R Okamoto, Nishmomlya; Hiromitsu 3,087,140 4/1963 ONeill 340/38 S Inoue, Kyoto; Hirokazu Mori, 3,199,074 8/1965 Hales 340/38 S Osaka; Mineo Okamoto, Hik ne all 3,343,167 9/1967 Rademacher 340/38 S f Japan 3,396,366 8 19 6 8 Migl ogk u ,.V34O/3 8 I SV 3,751,608 8/1973 Weingartner 179/182 R [73] Assignee: Matsushita Electric Works, Ltd.,

Osaka, Ja an p Primary Examiner-Ralph D. Blakeslee [22] 1972 Attorney, Agent, or FirmWolfe, Hubbard, Leydig, [21] Appl. No.1 246,537 Voit & Osann, Ltd.

[30] Foreign Application Priority Data May 31, 1971 Japan 46-45494 [57] ABSTRACT An ultrasonic transmitting and receiving device 2% 5" [79/1 z j g wherein horns are substantially vertically fitted to a l' l m frame so that p i g Side of the respective Fleld of Search SS, 1 E, H, horns be directed downward Each horn is P 182 181/31 27 81 vided in its throat section with an ultrasonic oscillator and in its opening with a reflector diagonally opposing [56] References Cited the Oscillator' UNITED STATES PATENTS 2 Claims 4 Drawing Figures 1,982,341 11/1934 Hitchcock 340/38 S 14 11, W 16 Xr 1 35 4 3 ;T@

9 s I9 l i% 1 I PATENIEDSEFI 0mm SHEET 1 OF 3 PRIOR A R T PATENIED sEP 1 01924 SHEET 3 UF 3 ULTRASONIC TRANSMITTING AND RECEIVING DEVICE This invention relates to ultrasonic transmitting and receiving devices.

In case ultrasonic oscillators to be used for transmitting and receiving ultrasonic waves are exposed to dust, rain water, snow or the like, unless they are of a special structure, their oscillation will be remarkably impeded and ultrasonic output or output voltage as of a microphone will reduce. In the case of conventional devices of this kind where the oscillator is fitted horizontally and a horn for focusing sound waves is fitted to it, rain water, dust or the like will enter the horn through the upper part and will be deposited onto the oscillator and, therefore, its oscillation will be remarkably impeded.

The present invention has been suggested to eliminate the above mentioned defect. According to the present invention, the oscillator is fitted vertically and a horn for focusing sound waves is fitted to the oscillator so as to be directed with its opening downward so that rain water, dust or the like will not enter the horn, and a reflector to reflect ultrasonic waves is provided diagonally in the opening of the horn so that ultrasonic waves will be projected horizontally while the oscillator is positioned vertically and thus the above mentioned defect will be solved.

A principal object of the present invention is, therefore, to provide an ultrasonic transmitting and receiving device wherein rain water, dust or the like will not be deposited to the oscillators.

Another object of the present invention is to provide an ultrasonic transmitting and receiving device wherein the projecting direction of ultrasonic waves from the transmitter can be changed in a simple manner.

The present invention shall be explained in the following with reference to the drawings in which:

FIG. 1 shows a conventional device; and

FIGS. 2 to 4 show a device embodying the present invention, wherein FIG. 2 is a sectioned view;

FIG. 3 is a sectioned view on line X X in FIG. 2; and

FIG. 4 is a perspective view of the device as disassembled.

In FIG. 1 showing a conventional ultrasonic transmitting and receiving device, a is an oscillator, b is a horn which is disposed horizontally. In this arrangement, rain water c will readily reach the oscillator a so as to cause the operation of the oscillator impeded.

An embodiment of the present invention shall be explained in the following with reference to FIGS. 2 to 4, in which 1 is a flat shaped mounting base having two sets of fitting holes 2 and 3. 4 and 4' are resilient L- shaped holding metal pieces each of which comprising a mounting leaf 35 provided with holes 7 for fitting the holding metal member to the mounting base 1 and a rectangular bent part 35' provided with a hole 5 for pivoting a holding frame, screw holes 6 for fitting a cover thereto and a bent tab 28 projected inward. The holding metal pieces 4 and 4' are fixed respectively to the upper part and lower part of the mounting base 1 by screwing screws into the holding metal piece fitting holes 3 in the base 1 through the holes 7 in the metal members 4 and 4'. 8 is a holding frame provided on its front surface with a pair of openings 9 and 9 and at the upper and lower ends with vertical stubs 10 for engaging with the holding metal pieces. Rear side of the frame 8 is opened at rear opening 11 which is covered by a lid 13 which is fitted on the inside surface with a felt or any other sound absorbing material 12. 14 is a plurality of shielding plates provided integrally to project parallelly with each other on the front surface between the front openings 9 and 9' of the holding frame 8. 15 is a transmitter which is provided with a reflector 19 disposed as inclined by about 45 with respect to the central axis of a horn 18 in a downward opening 17 of the horn 18 gradually expanded in the caliber toward the opening 17 from its throat 16, and contains in the throat 16 of the horn 18 a transmitting transducer 20 for converting an electric power to ultrasonic waves. This transmitting transducer 20 is made, for example, by properly fitting a piezoelectric element with a pair of electrodes. When a high frequency voltage is impressed between the respective electrodes, the piezoelectric element will oscillate due to a piezoelectric phenomenon to generate ultrasonic waves which will propagate from the throat 16 to the opening 17 of the horn so as to be reflected by the reflector 19 and projected in a direction substantially at right angles with respect to the central axis of the horn 18. When the natural frequency of the elastic oscillation of the piezoelectric element coincides substantially with the frequency of the high frequency voltage impressed between the electrodes, the transmitting transducer 20 will generate ultrasonic waves efficiently. 21 is a receiver which is provided with a diagonal reflecter 25 in the opening 23 of a horn 24 gradually expanded in the caliber toward its opening 23 from its throat 22 and contains in the throat 22 of the horn 24 a receiving transducer converting received ultrasonic waves to an electric power. This receiving transducer 26 is made, for example, the same as the transmitting transducer 20, by properly fitting a piezoelectric element with a pair of electrodes. When the piezoelectric element is oscillated by ultrasonic waves, a voltage will be generated between the respective electrodes by the piezoelectric phenomenon. The transmitter 15 and receiver 21 are contained respectively in the lower and upper parts of the holding frame 8 so as to form a transmitting and receiving device 27. The transmitter 15 is contained in the holding frame 8 so that ultrasonic waves projected in the direction substantially at right angles with respect to the central axis of the horn 18 will be reflected by the reflector l9 and radiated through the opening 9 of the holding frame 8, and the receiver 21 is contained in the holding frame 8 so that ultrasonic waves reflected from an object to be detected and propagated into the holding frame 8 through the opening 9' will be reflected by the reflector 25 and further propagated to the throat 22 through the opening 25. In such case, the ultrasonic waves transmitted through the opening 9 of the holding frame 8 will not propagate directly to the opening 9' of the receiving side as interrupted by the shielding plates 14.

The transmitting and receiving device 27 is mounted on the mounting base 1 so as to be rotatable about the engaging stubs 10 and 10 as a center by engaging the engaging stubs l0 and 10 at the upper and lower ends of the holding frame 8 with the engaging holes 5 of the holding metal pieces 4 and 4' secured to the mounting base 1. In such case, the inward bent tabs 28 formed integrally with the holding metal pieces 4 and 4' will contact the upper and lower end surfaces of the holding frame 8 so as to prevent the transmitting and receiving device 27 from rotating by itself. 29 is a cover in which a metal screen 32 is fitted arcuately to each opening 30 of a cover frame 31 having the openings 30 which are opposing to the openings 9 and 9 of the holding frame 8 of the transmitting and receiving device 27, a decorative plate 33 is fitted to the outside surface of the cover frame 31 and the peripheral edge of the metal screen 32 is inserted and held between the periheral edge of the opening 30 and the decorative plate 33. The cover 29 is secured to the mounting base 1 so as to enclose the transmitting and receiving device 27 by screwing screws passed through holes 34 formed on the upper and lower end surfaces of the cover frame 31 into the screw holes 6 in the holding metal pieces 4 and 4'.

As the present invention is formed as mentioned above, when a high frequency voltage is impressed on the transmitting transducer 20, ultrasonic waves will be radiated through the opening 9 of the holding frame 8. The waves will be reflected by an object to be detected if exists and will be propagated into the holding frame 8 through the opening 9' of the holding frame. Thus returned waves will be reflected at the reflector 25 to be directed to the throat 22 through the opening 23 of the horn 24 to reach the receiving transducer 26 and thereby the waves will be converted to an electric power. if, for example, a switch is operated in response to the output power of the receiving transducer 26, ultrasonic waves transmitted out of the transmitter will be reflected by an object to be detected and will propagate to the receiver 21 so that the object will be detected by the operation of the switch in response to the output power of the receiving transducer 26.

Thus, in the present invention, a transmitting transducer for converting ultrasonic waves to an electric power is contained and disposed in the throat 16 of a horn 18 which is gradually expanded in the caliber toward its opening 17 from its throat l6 and a reflector 19 is disposed as inclined by about 45 to the central axis of the horn 18 in the opening 17 of the horn 18 to form a transmitter 15, so that ultrasonic waves generated by the transmitting transducer 20 will be reflected by the reflector 19 and transmitted in a direction at right angles with respect to the central axis of the horn l8 and, at the same time, a reflector is disposed as inclined by about with respect to the central axis of the horn 24 in the opening 23 of the horn 24 which is gradually expanded in the caliber toward its opening 23 from its throat 22 and a receiving transducer 26 converting ultrasonic waves to an electric power is contained and disposed in the throat 22 of the horn 24 to form a receiver 21, so that ultrasonic waves propagating to the receiver 21 at right angles with respect to the central axis of the horn 24 will be reflected by the reflector 25 so as to propagate to the receiving transducer 26 in the throat 22 of the horn 24. Therefore, as the central axes of the horns 18 and 24 are made vertical and the throats l6 and 22 of the horns l8 and 24 are set above in disposing the transmitter 15 and receiver 21, there are advantages that, when the transmitting and receiving device of the present invention is set out of doors, rain water or dust will not be deposited on the transmitting transducer 20 and receiving transducer 26 which are not proof against the deposition of water and, therefore, the natural frequency of the elastic oscillation of the piezoelectric element of each of the transmitting transducer 20 and receiving transducer 26 will not vary.

Further, in the present invention, as the transmitter 15 and receiver 21 are fixed to the holding frame 8 and are set to be integrally rotatable on the mounting base 1, there are advantages that the transmitting direction of ultrasonic waves of the transmitter 15 can be changed very simply and that, when the ultrasonic waves transmitted out of the transmitter 15 are reflected by the object to be detected and are propagated to the receiver 21, the ultrasonic waves will propagate at right angles with the opening plane of the opening 9 of the holding frame 8 and to the throat 22 of the receiver efficiently.

What is claimed is:

1. An ultrasonic transmitting and receiving device comprising the combination of a semi-cylindrical outer case having at least one opening in the front wall thereof, said opening extending around a major portion of the semicylindrical outer case so as to form an opening of substantially a semi-cylindrical screen mounted over said opening,

an inner case housed in said outer case and pivoted thereto so as to be rotatable around a vertical axis within said outer case for controlling the direction of transmission of ultrasonic waves, the inner case being rotatable independently of the outer case so that the outer case remains in a fixed position regardless of the position of the inner case,

a pair of chambers formed by said inner case and each having an opening in the front wall of said inner case, said pair of chambers being disposed above and below one another,

at least one shielding plate disposed on the front of said inner case between said openings of said pair of chambers and extending horizontally to block direct transmission of ultrasonic waves between said pair of chambers,

a pair of ultrasonic oscillating elements each of which is mounted in the upper region of one of said chambers and directed downwardly, one of said elements being an ultrasonic transmitter and the other being an ultrasonic receiver,

a pair of reflectors each of which is mounted in the lower region of one of said chambers spaced from the corresponding oscillating element and inclined by about 45 with respect to said vertical axis of said chambers, said reflectors facing the respective openings of the respective chambers,

and a pair of conical horns each of which is mounted between one of said ultrasonic oscillating elements and the corresponding reflector and expanding in diameter in the direction toward the reflector.

2. An ultrasonic transmitting and receiving device comprising the combination of a semi-cylindrical outer case having at least one opening in the front wall thereof,

a screen mounted over said opening,

a semi-cylindrical inner case housed in said outer case and having a smaller radial dimension than said outer case, said inner case being pivoted on said outer case to permit rotation of the inner case around a vertical axis within said outer case for controlling the direction of transmission of ultrasonic waves,

6 a pair of chambers formed by said inner case and ing in said chamber,

each havmg an opemng the from Wall of sald and an ultrasonic receiver located in the other of said inner case, said pair of chambers being disposed above and below one another,

an ultrasonic transmitter located in one of said cham- 5 bers and means for directing ultrasonic waves gen- Calvererated by said transmitter through the front openchambers and means for directing ultrasonic waves from the front opening in said chamber to said re- 

1. An ultrasonic transmitting and receiving device comprising the combination of a semi-cylindrical outer case having at least one opening in the front wall thereof, said opening extending around a major portion of the semi-cylindrical outer case so as to form an opening of substantially 180* , a semi-cylindrical screen mounted over said opening, an inner case housed in said outer case and pivoted thereto so as to be rotatable around a vertical axis within said outer case for controlling the direction of transmission of ultrasonic waves, the inner case being rotatable independently of the outer case so that the outer case remains in a fixed position regardless of the position of the inner case, a pair of chambers formed by said inner case and each having an opening in the front wall of said inner case, said pair of chambers being disposed above and below one another, at least one shielding plate disposed on the front of said inner case between said openings of said pair of chambers and extending horizontally to block direct transmission of ultrasonic waves between said pair of chambers, a pair of ultrasonic oscillating elements each of which is mounted in the upper region of one of said chambers and directed downwardly, one of said elements being an ultrasonic transmitter and the other being an ultrasonic receiver, a pair of reflectors each of which is mounted in the lower region of one of said chambers spaced from the corresponding oscillating element and inclined by about 45* with respect to said vertical axis of said chambers, said reflectors facing the respective openings of the respective chambers, and a pair of conical horns each of which is mounted between one of said ultrasonic oscillating elements and the corresponding reflector and expanding in diameter in the direction toward the reflector.
 2. An ultrasonic transmitting and receiving device comprising the combination of a semi-cylindrical outer case having at least one opening in the front wall thereof, a screen mounted over said opening, a semi-cylindrical inner case housed in said outer case and having a smaller radial dimension than said outer case, said inner case being pivoted on said outer case to permit rotation of the inner case around a vertical axis within said outer case for controlling the direction of transmission of ultrasonic waves, a pair of chambers formed by said inner case and each having an opening in the front wall of said inner case, said pair of chambers being disposed above and below one another, an ultrasonic transmitter located in one of said chambers and means for directing ultrasonic waves generated by said transmitter through the front opening in said chamber, and an ultrasonic receiver located in the other of said chambers and means for directing ultrasonic waves from the front opening in said chamber to said receiver. 